1. Technical Field
The present invention relates to a cap, a fastening structure using the same, and an aircraft including the fastening structure.
2. Description of the Related Art
A skin constituting the body of an aircraft is reinforced from inside with a structural member that is a frame member formed in a grid configuration.
The skin and the structural member located inside the skin are bonded with a fastener. Since the fastener is made of a metal (for example, a titanium alloy), there is the possibility that a bolt of lightning strike may pass through the fastener and generate sparks internally.
For this reason, a structure for inhibiting a bolt of lightning from passing though the fastener has been proposed, for example, as disclosed in Japanese Unexamined Patent Application, Publication No. 2007-126119.
In the structure disclosed in JP 20007-126119, an insulating cap is mounted at the outer end of the head of a fastener, and many structures have been proposed that inhibit the passage of a bolt of lightning by devising the structure of the fastener in this way.